JP2006181675A - Rotation limit device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotation limit device allowing reduction of size and weight, while widening a movable range as much as possible. <P>SOLUTION: This rotation limit device 10 is provided with a fixed part 2 having a stopper member 1, a free rotating part 4 having a projection member 3 capable of contacting the stopper member 1 and arbitrarily rotatable in a left and right direction, and a rotating part 6 formed with a circular-arc shaped slit 5 engaged with the projection member 3. The projection member 3 is provided in the free rotating part 4 arranged between the rotating part 6 and the fixed part 2 to rotate up to an angle larger than a rotary angle determined by the length of the slit 5 of the rotating part 6. Since the fixed part 2 is provided with the stopper member 1, the movable range of the rotation limit device 10 is widened without providing a movable stopper at the outside of the rotating part 6. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rotation limit device that can rotate by a predetermined range.

  In general, an apparatus having a rotating joint such as a robot requires a mechanism for mechanically limiting the rotating operation on the rotating unit side and preventing over-rotation. Usually, the rotational operation range is generally set to 1 rotation or less, but a mechanism that enables an operation range of 1 rotation or more is also required in some cases.

As one of this type of mechanism, there is known a rotation limit device in which a movable stopper is provided and the rotation range of the rotating portion can be set wide (see, for example, Patent Document 1). The limit device disclosed in this document is provided with a movable stopper on the outside of the rotating portion, and the stopper is brought into contact with each of two members capable of relative rotation, thereby limiting the total rotation amount of the rotating joint. It is set to more than °.
JP-A-7-136972

  As described above, the conventional rotation limit device has a configuration in which a movable stopper is disposed outside the rotating portion. Therefore, the total amount of rotation that can be limited is within a range of ± (180 degrees + about 45 degrees), and there is a problem that the movable range cannot be expanded beyond this range.

  In addition, since the mechanism including the movable stopper is disposed outside the rotating unit, the entire rotation limit device becomes larger than the rotating unit. For this reason, this type of rotation limit device is not suitable for incorporation into robots, particularly mobile robots that need to be reduced in size and weight.

  In addition, for a rotating joint, a function is usually provided to place a sensor in front of the mechanical stopper to detect the rotational position and prevent the controller from rotating further for safety and equipment maintenance. Need. However, the conventional rotation limit device including the above-mentioned Patent Document 1 does not have a function of detecting the rotation position or a function of stopping the rotation before contacting the stopper.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a rotation limit device that can expand the movable range as much as possible and can be reduced in size and weight.

  In order to solve the above-described problems, according to one aspect of the present invention, a fixed portion having a stopper member, a free rotating portion having a protruding member that can contact the stopper member and capable of free rotation, and the free portion And a rotating part having a common center axis and a slit in which the protruding member is engaged.

  According to the present invention, a rotation limit device that can be reduced in size and weight while expanding the movable range as much as possible can be realized, and can be widely applied to a rotary joint of a robot.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is an exploded perspective view of the rotation limit device according to the first embodiment of the present invention, and FIG. 2 is an assembled perspective view of the rotation limit device.

  As shown in these drawings, the rotation limit device 10 according to the first embodiment has a fixed portion 2 having a stopper member 1 and a protruding member 3 that can come into contact with the stopper member 1 and can be arbitrarily rotated to the left and right. A free rotating part 4 and a rotating part 6 formed with an arcuate slit 5 with which the protruding member 3 is engaged. The fixed portion 2, the free rotating portion 4 and the rotating portion 6 are all disk-shaped, and are formed with holes 7 having substantially the same diameter near the center. 4 and the rotation part 6 can be rotated counterclockwise and clockwise. The fixed portion 2 and the free rotating portion 4 have annular ribs 8 and 9 formed along the holes 7, and the annular ribs 8 and 9 are arranged above the free rotating portion 4 or the rotating portion 6. The lower surface is rotatably engaged.

  The slit 5 of the rotating part 6 is formed in an arc shape along the shape of the peripheral part of the rotating part 6. Position detectors 11 and push-back springs 12 are provided at both ends of the slit 5.

  3 is a top view showing the structure around the position detector 11, and FIG. 3A is a view showing a state in which the protruding member 3 is in contact with the push-back spring 12 (a state in which the push-back spring 12 is not pushed in). (B) has shown the state which the protrusion member 3 has pushed in the push-back spring 12. FIG. The position detector 11 is concave as shown in FIGS. 1 and 2 and is disposed so as to straddle the slit 5. One end of a push-back spring 12 is attached to the end of the slit 5. The position detector 11 detects the protruding member 3 when the protruding member 3 pushes the push-back spring 12 and the protruding member 3 comes directly below the position detector 11 as shown in FIG. The position detector 11 is composed of, for example, a photo interrupter or the like, and optically detects the protruding member 3. The detection method of the position detector 11 is not particularly limited.

  The detection result of the position detector 11 is transmitted to the control device 13. When the position detector 11 detects the protruding member 3, the control device 13 determines that it cannot continue further rotation, and can perform control to rotate the rotating unit 6 in the reverse direction.

  Although omitted in FIGS. 1 to 3, an actuator for rotating the rotating unit 6 to the left and right by a control signal from the control device 13 is provided. Various wirings such as control signals are arranged inside the hole 7 at the center of the fixed portion 2, the free rotating portion 4 and the rotating portion 6. For this reason, no matter how much the rotation limit device 10 is rotated to the left or right, there is no possibility that the wiring is caught or wound around other members.

  FIG. 4 is a diagram illustrating an example of the rotation operation of the rotation limit device 10 according to the first embodiment. Hereinafter, the operation of the rotation limit device 10 will be described with reference to FIG. Suppose that the protruding member 3 is at the position shown in FIG. 4A, and the rotating portion 6 is rotated leftward with this position as the origin.

  When the rotating unit 6 rotates leftward in the state of FIG. 4A, the protruding member 3 comes into contact with the push-back spring 12 as shown in FIG. 4B. In this state, when the rotating portion 6 further rotates leftward, the projecting member 3 does not bias the pushback spring 12, and the projecting member 3 and the pushback spring 12 both rotate leftward while being in contact with each other.

  Eventually, the protruding member 3 comes into contact with the stopper member 1. If the rotating part 6 is further rotated in the left direction in this state, the protruding member 3 is in contact with the stopper member 1 and the free rotating part 4 cannot move. Therefore, as shown in FIG. 3 presses the push-back spring 12. When the push-back spring 12 is pressed to a certain extent, the position detector 11 detects the protruding member 3 as shown in FIG. The control device 13 shown in FIG. 3 performs control so as to change the rotation direction of the rotating unit 6 in response to detection by the position detector 11. Thereby, a temporary rotation limit can be applied.

  If the control device 13 does not apply such a rotation limit, the push-back spring 12 contracts to the limit position and is completely mechanically limited.

  FIG. 5 is a diagram illustrating the rotation angle of the rotation limit device 10 according to the present embodiment. In FIG. 5, an angle between both ends of the slit 5 of the rotating unit 6 is α, and an angle from the end of the slit 5 to the stopper member 1 is β. In this case, the angle at which the rotating unit 6 rotates alone is α, and the angle at which both the rotating unit 6 and the free rotating unit 4 rotate is β. Therefore, as a whole, it can rotate leftward by an angle (α + β). Moreover, it has the same movable range also with respect to the right direction. Accordingly, a movable range of 360 degrees or more can be obtained as a whole.

  The longer the slit 5 of the rotating unit 6 is along the peripheral shape, the larger the angle α and the larger the rotation angle of the rotation limit device 10. Actually, by making the slit 5 longer, the rotation angle can be expanded to about ± 350 degrees in one direction.

  Further, according to the present embodiment, even when the rotation angle of the rotation limit device 10 is widened, the position detector 11 detects the position of the protruding member 3 and rotates immediately before applying the mechanical stopper by the stopper member 1. Limits can be applied, and mechanical unreasonable force is not applied, making it difficult to break. Therefore, the reliability of the rotation limit device is improved.

  FIG. 6 is a top view showing a modification of the rotation limit device 10 according to the first embodiment. The rotation limit device 10 in FIG. 6 is provided with a lever 14 instead of the push-back spring 12. The levers 14 are rotatable about one end as a rotation shaft 15, and a torsion spring 16 is attached to the rotation shaft 15. When the rotating portion 6 continues to rotate, the protruding member 3 eventually contacts the lever 14. When the rotating unit 6 is further rotated, the protruding member 3 and the lever 14 rotate together in contact with each other, and the protruding member 3 eventually contacts the stopper member 1. When the rotating unit 6 is further rotated, the protruding member 3 pushes the lever 14. When the rotation of the rotating unit 6 is stopped in this state, the protruding member 3 is pushed back by the biasing force of the lever 14.

  The push-back spring 12 and the lever 14 are examples, and various elastic members can be used.

  Thus, in the first embodiment, the free rotating unit 4 disposed between the rotating unit 6 and the fixed unit 2 is configured to be able to rotate to an angle larger than the rotation angle determined by the slit 5 length of the rotating unit 6. Since the protruding member 3 is provided and the stopper member 1 is provided on the fixed portion 2, the movable range of the rotation limit device 10 can be expanded without providing a movable stopper outside the rotating portion 6. Therefore, it is possible to obtain the rotation limit device 10 that can be easily reduced in size and weight and can be easily applied to a rotary joint or the like of a robot.

(Second Embodiment)
In the second embodiment, a plurality of free rotating portions 4 are provided.

  FIG. 7 is an exploded perspective view of the rotation limit device 10 according to the second embodiment of the present invention. In the rotation limit device 10 in FIG. 7, a plurality of free rotation parts 4 a, 4 b, 4 c are arranged between the rotation part 6 and the fixed part 2 having the same structure as in FIG. 1. Although FIG. 7 shows an example in which three free rotating portions 4a to 4c are provided, the number of free rotating portions is not particularly limited.

  In the following, the top free rotation part is the first free rotation part 4a, the second free rotation part from the top is the second free rotation part 4b, and the bottom free rotation part is the third free rotation part. Called 4c.

  The third free rotating portion 4 c has a shape similar to that of the free rotating portion 4 of FIG. 1 and has a protruding member 3 c that can contact the stopper member 1. The first and second free rotating parts 4a and 4b have arcuate slits 5a and 5b and projecting members 3a and 3b, respectively. The protruding member 3c of the third free rotating part 4c is engaged with the slit 55b of the second free rotating part 4b. The protruding member 3b of the second free rotating part 4b is engaged with the slit 5a of the first free rotating part 4a. The protruding member 3 a of the first free rotating part 4 a is engaged with the slit 5 of the rotating part 6.

  For example, when the rotating portion 6 is rotated leftward, the protruding member 3a of the first free rotating portion 4a eventually contacts the pushback spring 12 of the rotating portion 6, and this protruding member 3a rotates leftward together with the pushback spring 12. To do. That is, the rotating part 6 can rotate by the length of the slit 5 independently.

  When the push-back spring 12 of the rotating part 6 and the projecting member 3a of the first free rotating part 4a come into contact with each other and rotate together, the first free rotating part 4a rotates by the length of the slit 5a. . When the protruding member 3b of the second free rotating part 4b contacts the end of the slit 5a of the first free rotating part 4a, the second free rotating part 4b starts rotating this time. The second free rotating portion 4b rotates by the length of the slit 5b at the maximum.

  When the protruding member 3 of the third free rotating part 4c comes into contact with the end of the slit 5b of the second free rotating part 4b, the third free rotating part 4c starts rotating. The third free rotating portion 4c rotates by the length of the slit 5c at the maximum.

  The third free rotating portion 4 c rotates until the protruding member 3 c comes into contact with the stopper member 1 of the fixed portion 2. Even if the protruding member 3 of the third free rotating portion 4c contacts the stopper member 1 of the fixed portion 2, if the rotating portion 6 is still rotated leftward, the push-back spring 12 of the rotating portion 6 is moved to the first free rotating portion. It is pushed in by the protruding member 3a of 4a. When the push-back spring 12 is gradually pushed in by the protruding member 3a, the protruding member 3a is eventually detected by the position detector 11, and a limit is imposed on the leftward rotation.

  After all, in the case of the rotation limit device 10 of FIG. 7, in the left-right direction, (rotation angle by the length of the slit 5 of the rotation unit 6) + (rotation angle by the length of the slit 5a of the first free rotation unit 4a) + (second The rotation angle due to the length of the slit 5b of the free rotation portion 4b) + (the rotation angle due to the length of the slit 5c of the third free rotation portion 4c) + (the projection member 3c of the third free rotation portion 4c is the stopper member 1 of the fixed portion 2) Rotation angle according to the length until it touches.

  As described above, in the second embodiment, by providing the plurality of free rotation portions 4a, 4b, and 4c, the rotation angle can be made larger than that in the first embodiment, and a movable range of 360 degrees or more can be secured. Moreover, in principle, the rotation angle can be expanded infinitely by increasing the number of the free rotation parts 4, and a desired amount of rotation can be obtained by adjusting the number of the free rotation parts 4.

(Third embodiment)
In the third embodiment, a mechanism for automatically returning the protruding member of the free rotating portion 4 to the origin position is provided.

  FIG. 8 is an exploded perspective view of the rotation limit device 10 according to the third embodiment of the present invention, and FIG. 9 is a top view thereof. The rotation limit device 10 shown in FIG. 8 includes a fixed portion 2, a free rotation portion 4, and a rotation portion 6, as in the first and second embodiments.

  In addition to having the stopper member 1 similar to that in FIG. 1, the fixed portion 2 has a photo interrupter 21 for detecting the rotation direction of the free rotating portion 4.

  The free rotating portion 4 has a protruding member 3 similar to that shown in FIG. 1, and a notch 22 is formed at a part of the peripheral edge. As will be described later, the notch 22 is used by the photo interrupter 21 to detect the rotation direction of the free rotation unit 4. The protruding member 3 of the free rotating portion 4 is disposed on an extension line of the end portion of the notch portion 22.

  The photo interrupter 21 of the fixed portion 2 has a concave shape, and the free rotating portion 4 is disposed in the recessed portion of the photo interrupter 21. The free rotating part 4 is formed of a light shielding plate and blocks light emitted from the photo interrupter 21. However, when the cutout portion 22 of the free rotating portion 4 passes directly below the photointerrupter 21, the light emitted from the photointerrupter 21 is received without being blocked. Therefore, the rotation direction of the free rotation part 4 can be detected based on whether or not the cutout part 22 has passed directly under the photo interrupter 21.

  The rotating unit 6 includes an arc-shaped slit 5 and an origin return mechanism 23 provided in the slit 5. The origin return mechanism 23 includes two levers 24 and 25 arranged in close contact with each other, and the connection point of these levers 24 and 25 is the origin. Each of the levers 24 and 25 can rotate in a certain angle range around a rotation axis arranged in the vicinity of the origin, and applies a biasing force toward the origin. For example, when the protruding member 3 is located at a position other than the position (origin) where it contacts the lever, the protruding member 3 is pushed out toward the original position by the two levers 24 and 25. As a result, the projecting member 3 is given an urging force so as to return to the origin regardless of the position in the slit 5.

  FIG. 10 is a diagram for explaining the operation of the rotation limit device 10 according to the third embodiment. In the initial state, as shown in FIG. 9, the protruding member 3 is arranged at the origin position of the rotating unit 6 by the origin returning mechanism 23 of the rotating unit 6. It is assumed that the rotating unit 6 is rotated leftward from this state. At this time, as shown in FIG. 10A, the photo interrupter 21 passes through the cutout portion 22 of the free rotating portion 4, and therefore the photo interrupter 21 does not react at all. While the protruding member 3 of the free rotating portion 4 is held at the origin position of the rotating portion 6, both the free rotating portion 4 and the rotating portion 6 rotate leftward.

  Eventually, when the protruding member 3 comes into contact with the stopper member 1 of the fixed portion 2, the free rotating portion 4 can no longer rotate, but the rotating portion 6 continues to rotate leftward. As the rotating unit 6 rotates, the protruding member 3 biases the lever 24 of the origin return mechanism 23, and the protruding member 3 relatively moves toward the end of the lever 24 of the origin return mechanism 23.

  If the rotation in the left direction is continued as it is, the projecting member 3 comes into contact with the pushback spring 12 and the projecting member 3 pushes the pushback spring 12 to some extent, but the position detector 11 detects the projecting member 3. Here, when the control device 13 stops the rotation operation of the rotation unit 6, the protruding member 3 is returned to the origin of the free rotation unit 4 by the biasing force of the lever of the origin return mechanism 23 as shown in FIG. 9.

  In the case of the rotation limit device 10 according to the third embodiment, the rotating unit 6 rotates by 180 ° or more with respect to the fixed unit 2, but the free rotating unit 4 rotates by less than 180 ° with respect to the fixed unit 2. For this reason, when the rotating part 6 is rotating leftward from the origin, the location of the photo interrupter 21 passes only the notch part 22 of the free rotating part 4, and the photo interrupter 21 is the light shielding plate of the free rotating part 4. Is not detected.

  On the other hand, FIG.10 (c) is a top view which shows the case where the rotation part 6 is rotated rightward from the state of FIG. In this case, the photo interrupter 21 always detects the light shielding plate of the free rotating unit 4, and the control device 13 that receives a signal from the photo interrupter 21 recognizes that the rotation limit device 10 is rotating in the right direction.

  For example, with respect to the origin, the rotation angle of 200 ° and the rotation angle of −160 ° are different only in the rotation direction, and the positions after the rotation are the same. On the other hand, according to the present embodiment, it is possible to accurately detect in which direction the rotation has occurred.

  Thus, in the third embodiment, the position detection notch 22 is provided in the free rotation part 4, the protruding member 3 is disposed at the end of the notch 22, and the origin return mechanism is provided in the rotation part 6. 23 and the photointerrupter 21 for detecting the light shielding plate of the free rotating portion 4 is provided in the fixed portion 2, so that the movable range can be expanded and the rotational direction can be detected accurately.

(Fourth embodiment)
The fourth embodiment is a modification of the third embodiment, in which a plurality of free rotating parts 4 are provided between the rotating part 6 and the fixed part 2.

  FIG. 11 is an exploded perspective view of the rotation limit device 10 according to the fourth embodiment of the present invention. The rotation limit device 10 of FIG. 11 includes three free rotation portions 4 a, 4 b, 4 c between the rotation portion 6 and the fixed portion 2. The number of free rotating parts is not particularly limited. Below, the three free rotation parts 4 are called the 1st, 2nd, and 3rd free rotation parts 4a, 4b, and 4c from the side near the rotation part 6. FIG.

  The rotating unit 6, the fixed unit 2 and the third free rotating unit 4c have the same shapes as the rotating unit 6, the fixed unit 2 and the free rotating unit 4 of FIG. The first and second free rotating parts 4a and 4b include arc-shaped slits 5a and 5b, push-back springs 12 disposed at both ends of the slits 5a and 5b, and an origin return mechanism 23a disposed in the slit 5. , 23b. The fixed part 2, the second and third free rotating parts 4b and 4c have photo interrupters 21, 21a and 21b, respectively. The 1st-3rd free rotation parts 4a-4c have the notch parts 22a-22c formed along the periphery, respectively.

  The photo interrupter 21a of the second free rotation unit 4b detects the rotation direction of the first free rotation unit 4a, and the photo interrupter 21b of the third free rotation unit 4c detects the rotation direction of the second free rotation unit 4b. The photo interrupter 21 of the fixed unit 2 detects the rotation direction of the third free rotation unit 4c.

  The rotation limit device 10 in FIG. 11 can rotate by the same amount of rotation as in FIG. 7 on the same principle as in FIG. 7 except that it includes the origin return mechanism 23 and a rotation direction detection function.

  As described above, in the fourth embodiment, by providing the plurality of free rotating portions 4, the movable range can be expanded, and the rotation direction of the first to third free rotating portions 4 c can be accurately detected.

  The rotation limit device 10 described in each embodiment described above can be used for, for example, a joint portion of a robot. Since the rotation limit device 10 of the present invention can be reduced in size and weight, it can also be applied to a small robot such as a mobile robot. By incorporating the rotation limit device 10 according to the present invention into a robot, the performance of the robot can be improved. .

1 is an exploded perspective view of a rotation limit device according to a first embodiment of the present invention. The assembly perspective view of a rotation limit device. The top view which shows the structure of the position detector 11 periphery. The figure which shows an example of rotation operation | movement of the rotation limit apparatus 10 which concerns on 1st Embodiment. The figure explaining the rotation angle of the rotation limit apparatus 10 which concerns on this embodiment. The top view which shows the modification of the rotation limit apparatus 10 which concerns on 1st Embodiment. The disassembled perspective view of the rotation limit apparatus 10 which concerns on the 2nd Embodiment of this invention. The disassembled perspective view of the rotation limit apparatus 10 which concerns on the 3rd Embodiment of this invention. The top view of the rotation limit apparatus 10 which concerns on the 3rd Embodiment of this invention. The figure explaining operation | movement of the rotation limit apparatus 10 which concerns on 3rd Embodiment. The disassembled perspective view of the rotation limit apparatus 10 which concerns on the 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stopper member 2 Fixed part 3 Protrusion member 4 Free rotation part 5 Slit 6 Rotation part 11 Position detector 12 Push-back spring 21 Photo interrupter 22 Notch part

Claims (11)

A fixed portion having a stopper member;
A free rotating part having a protruding member that can contact the stopper member and capable of free rotation;
A rotation limit device comprising: a rotation portion having a common center axis with the free rotation portion, and a slit formed with a slit with which the protruding member is engaged.   The rotating part performs a rotation operation without rotating the free rotating part until the protruding member reaches the end of the slit, and when the protruding member reaches the end of the slit, the protruding member is The rotation limit device according to claim 1, wherein the rotation limit device rotates with the free rotation portion until it comes into contact with a stopper member. The rotating part is
An elastic member disposed at an end of the slit, capable of being contracted by the projecting member, and biasing the projecting member in a direction opposite to the contracting direction;
A position detector that is disposed at an end of the slit and detects whether or not the protruding member has passed when the protruding portion contracts the elastic member by a predetermined amount or more. The rotation limit device according to claim 2.   The rotation limit device according to claim 3, further comprising a control unit that stops the rotation of the rotating unit or reverses the rotation direction when the position detecting unit detects the passage of the protruding member. The fixed portion, the free rotating portion, and the rotating portion are each formed of a disc with a central portion that is hollowed out with a central axis in common,
The rotation limit device according to claim 1, wherein the slit is formed in an arc shape along a peripheral shape of the rotating portion.   The wiring connected to at least one of the fixed portion, the free rotating portion, and the rotating portion is disposed inside a hole in a central portion of the fixed portion, the free rotating portion, and the rotating portion. The rotation limit device according to claim 5. A plurality of the free rotating parts are provided between the fixed part and the rotating part,
Of the plurality of free rotating portions, the other free rotating portions except the free rotating portion arranged at the bottom are engaged with the protruding members of the other free rotating portions arranged adjacent to the lower side thereof. The rotation limit device according to claim 1, further comprising a slit.   6. The rotation limit device according to claim 1, wherein the rotation unit includes a return mechanism that returns the protruding member to a predetermined origin position when no rotational driving force is applied.   The rotation limit device according to claim 8, further comprising a moving direction detection unit that detects whether the protruding member has moved in a left or right direction from the origin position. The free rotating part has a notch formed in a part of the outer peripheral edge along the outer peripheral edge,
10. The rotation limit according to claim 9, wherein the moving direction detection unit is provided in the fixed unit and optically detects whether or not the notch has passed during rotation of the free rotation unit. apparatus. A plurality of the free rotating parts are provided between the fixed part and the rotating part,
Of the plurality of free rotating portions, the other free rotating portions except the free rotating portion arranged at the bottom are engaged with the protruding members of the other free rotating portions arranged adjacent to the lower side thereof. Having a slit and the notch,
Of the plurality of free rotating parts, the other free rotating parts other than the free rotating part arranged at the top have passed through the notch of the free rotating part arranged adjacent to the upper side. The rotation limit device according to claim 10, further comprising the moving direction detection unit that detects optically.

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